The addon is great, but I would like one more feature. Most computer screens, if not all of them, are wider than higher. I think it would be a very cool feature would be to distinguish between maxsize width and maxsize height.

For example, let's say my "Maximum image size:" is 600px because I design for 1024x768px. For a 1000x2000px image the auto setting is ok and would produce a 300x600px image.
However, for a 2000x500px panorama, I do not want it to be 600x150px but something like 900x225px.
As wide screen are becoming popular this is an even more important point.